That Glass may be rendred malleable and pliable unto the hammer, many conceive, and some make little doubt, when they read in _Dio_, _Pliny_, and _Petronius_, that one unhappily effected it for _Tiberius_. Which notwithstanding must needs seem strange unto such as consider, that bodies are ductile from a tenacious humidity, which so holdeth the parts together; that though they dilate or extend, they part not from each others. That bodies run into Glass, when the volatile parts are exhaled, and the continuating humour separated: the Salt and Earth, that is, the fixed parts remaining. And therefore vitrification maketh bodies brittle, as destroying the viscous humours which hinder the disruption of parts. Which may be verified even in the bodies of Metals. For Glass of Lead or Tin is fragile, when that glutinous Sulphur hath been fired out, which made their bodies ductile. He that would most probably attempt it, must experiment upon Gold. Whose fixed and flying parts are so conjoined, whose Sulphur and continuating principle is so united unto the Salt, that some may be hoped to remain to hinder fragility after vitrification. But how to proceed, though after frequent corrosion, as that upon the agency of fire, it should not revive into its proper body before it comes to vitrifie, will prove no easie discovery. 3. That Gold inwardly taken, either in substance, infusion, decoction or extinction, is a cordial of great efficacy, in sundry Medical uses, although a practice much used, is also much questioned, and by no man determined beyond dispute. There are hereof I perceive two extream opinions; some excessively magnifying it, and probably beyond its deserts; others extreamly vilifying it, and perhaps below its demerits. Some affirming it a powerful Medicine in many diseases, others averring that so used, it is effectual in none: and in this number are very eminent Physicians, _Erastus_, _Duretus_, _Rondeletius_, _Brassavolus_ and many other, who beside the strigments and sudorous adhesions from mens hands, acknowledge that nothing proceedeth from Gold in the usual decoction thereof. Now the capital reason that led men unto this opinion, was their observation of the inseparable nature of Gold; it being excluded in the same quantity as it was received, without alteration of parts, or diminution of its gravity.